For years and years, the ‘perfect school’ was defined by having the right ratio of black to white, native to migrant and rich to poor. However, recent Dutch research has exposed this myth. Children at mixed schools consistently score lower grades than their peers at predominantly white or black schools. Dutch sociology professor Jaap Dronkers has carried out research into the pros and cons of ethnic diversity in secondary education. He compared student achievement in language, math and physics of 15-year-old children in 15 Western countries. Much to his surprise, students’ grades were inversely proportional to ethnic diversity.

“I interpret lower student achievement at ethnically diverse schools to mean that a great deal of energy is spent on bridging the various cultural gaps between students. […]

Another noteworthy finding from his research are the generally below-average achievements of students with an Islamic background. “This cannot be explained by their socio-economic backgrounds or the characteristics of schools or educational systems. So what is the reason? It is very well possible that they are being discriminated against, but this also holds true for non-Islamic children. People will say: they are the children of migrant workers, but so were the Italians. The remaining factor is religion.” […]

Dutch writer and educational expert Anja Vink says the professor places too much emphasis on culture and religion. She argues that socio-economical circumstances are widely accepted as determining factors for the educational achievement of children. […]

Professor Dronkers agrees that ethnic diversity can have a positive effect on children of highly educated parents. “In that case there is an added value.” The scientist says that migrant children from non-Islamic countries like China, South Korea and India are also a positive exception to the rule. Lower achievements at mixed schools

Our projections for many west European countries find that Muslims will make up between 4 and 14 per cent of the population by 2030, a large increase from the 2-6 per cent range today, but a far cry from Eurabia. Sweden will be the most Islamic country in Europe. Britain`s Muslim population will be close to 7 per cent, compared to 2.8 per cent in 2001 (and a 2009 estimate of 4 per cent). Some might be tempted to glide from careful projection to a prophecy of a doubling of the Muslim share every 20 years. This would produce a Muslim majority in a few generations and vindicate the predictions of extreme Eurabianists.

A seven-minute YouTube video, “Muslim Demographics,” took the internet by storm in 2009, attracting more than 10m hits. The video gives the low birthrates of Europe`s native populations and, country by country, contrasts them with the high fertility rates of European Muslims. It then careers off into fantasy, claiming the average French Muslim woman bears 8.1 children (it is around three), and that 30 per cent of French people under 20 are Muslim (the real figure is 5.7 per cent). Even so, the video paints a seemingly convincing picture of a Muslim reconquista by 2050—the point is that Muslims could peacefully conquer Europe by simple demographics, as Libya`s Muammar Gaddafi claims. Welcome to the world of those worrying about the creation of a new continent: Eurabia.

Eurabianism abounds online, apparently touching on widely held anxieties. Most of it is exaggeration, and easy for liberal commentators to dismiss as an alarmist fantasy. But those who reject the fantasies often too airily reject more plausible arguments. Eurabia sceptics fail to appreciate that seemingly minor differences in fertility and immigration, if sustained over time, lead to compound effects which transform populations over the span of a century or two.

Rodney Stark, a sociologist of religion, has shown how a slight demographic advantage for early Christians—a function of superior care of their sick, a family-centred ethos and a high percentage of female converts—explains much of the increase in their ranks between 30 and 300AD. Stark says 40 per cent growth per decade is sufficient to account for the expansion of the “Jesus movement” from 40 to 6m converts in the period prior to Christianity becoming Rome`s official religion. The Mormon religion has enjoyed the same rate of growth since its founding in 1830 and, if this continues, it will emerge as one of the major world religions in the next century. More recently, conservative American Protestants have increased from a 40 per cent minority of white Protestants born in 1900 to a two-thirds majority among those born in 1975. The slight fertility advantage of conservative over liberal Protestants accounts for three-quarters of the rise. In the US, the number of Latinos has soared, both because of immigration and a high birthrate. A trace element in 1960, they are now 15 per cent of the population. The US census bureau projects they will make up a quarter of the total in 2050.

So there is nothing impossible about a sharp growth in one population relative to another. It is also important to realise the truth in the saying that “demography is destiny.” Demography is the most predictable social science, much more so than economics. We can predict with a high degree of accuracy how many fiftysomethings there will be in the 2050s because they are already alive. In addition, we now have decades worth of data on immigration, intermarriage, secularisation and fertility trends which we can build models from.

What, then, is the real evidence for Eurabia? Awkwardly, most European censuses do not ask an ethnicity question and only four—Austria, Switzerland, Britain and Slovakia—inquire about religion. However, there is now enough reliable survey data to make demographic projections for other countries. I have been involved in a research project on this issue, based at Austria`s International Institute for Applied Systems Analysis. We have produced the first rigorous projections of the religious composition of selected European countries to 2030. The full report will be released in April, and in my new book, Shall the Religious Inherit the Earth? (Profile), but the broader findings are already clear.

Let`s begin with the current Muslim share of the population (see chart, below). In all European nations these are small minorities, but they will rise sharply even without immigration because Muslim populations, like all immigrant groups, are much younger than average. In Britain, 4.7 per cent of those under 16 are Muslim compared to just 0.6 per cent of those over 65. And Muslim families are larger than others—in Britain, the total fertility rate (TFR) of Muslim women is about two-thirds higher than that of the median British woman.

If immigration stopped tomorrow, Muslims` higher fertility and young age structure would still ensure a rise in their share of the total, which would be most apparent in maternity wards and primary schools. Though Muslims are younger and more fertile than Sikhs, Buddhists and Hindus, this is not a solely Islamic phenomenon. In Britain in 2001, 8.5 per cent of the population was born abroad, but one in five births were to foreign-born mothers, rising to one in two in greater London. The corresponding figure for Paris is one in three.

What`s more, sharp cuts in immigration will probably not happen. Europe`s native population is ageing and declining. This will prompt a push for further economic migration by employers` groups among others. Asylum, chain migration and illegal immigration are difficult to control in liberal societies, so the flow of roughly 250,000 Muslims into the EU each year will probably continue. It sounds like a trickle, and at 0.5 per cent of the EU population it is. But the wave of Latino immigration to the US only averaged 1 per cent of the total per year and has transformed America. In short, there is enough evidence to back at least part of the Eurabia thesis.

What do the Eurabia sceptics have to say? In a recent article in Foreign Policy magazine, Justin Vaïsse of the Brookings Institution, an influential Washington think tank, dismissed a number of thinkers who have worried in public about the rise of Europe`s Muslim population. He attacked the “hyperbolic Mark Steyn, the shallow Bruce Thornton, the more serious Walter Laqueur, and the high-pitched Claire Berlinski and Bruce Bawer.” It is true that some Eurabianists are ideologically driven journalists who rely on anecdotes and statistical distortion. That said, others like French demographer Jean-Claude Chesnais cannot be so easily brushed aside.

More sober Eurabianists, such as theologian George Weigel or journalist and author Christopher Caldwell, place the advent of a Muslim Europe in the early-to-mid 2100s rather than 2050. That may also be wrong, but it is fair to ask what the continent will look like if demographic drivers remain as they are. And it is here that liberal sceptics fail us. Vaïsse exposes the ropy statistics of some Eurabianists, yet offers no projection of his own. He simply declares that when it comes to the Muslim share of the population, “it`s hard to imagine that Europe will even reach the 10 per cent mark.”

Other sceptics claim that Muslims will increasingly integrate and leave Europe`s culture largely unchanged, but this is difficult to prove. Here intermarriage is arguably the best barometer of assimilation. Leo Lucassen and Charlotte Laarman of the University of Leiden have researched this area, focusing on Muslim populations in Germany, Belgium, Holland, Britain and France. They concluded that roughly 6 per cent of foreign-born Muslims married outside the faith, rising to 10-11 per cent by the second generation. Much of the increase can be attributed, however, to the somewhat exceptional integration of French Algerians. Overall, the level of Muslims marrying out remains low. In Germany, for instance, just 7.2 per cent of Muslim men and 0.5 per cent of Muslim women were married to someone of another religious faith.

To be fair, Sikhs and Hindus resemble Muslims in their level of endogamy (marrying people like you). Over 90 per cent of all south Asian groups in Britain marry their own. Few stray outside their national group even when both are Muslim: of more than 12,000 marriages in a 2001 census sample involving a Pakistani or a Bengali, there were 25 Pakistani-Bengali couples. Ironically, one of the few venues for inter-ethnic marriage are extreme groups like Hizb-ut-Tahrir, where shared Islamism can override more parochial ties. In short, European Muslims, like Hindus and Sikhs, are unlikely to quickly relinquish their group boundaries for the melting pot.

An alternative route to integration is secularism. If Muslims are turning into secular Europeans, demography is immaterial. Here again, though, group boundaries are holding. Europe-wide surveys find that Muslims under 25 are as devout as those over 55, a big contrast with Catholics or Anglicans. Muslim youth are often stricter than their elders: a 2006 poll discovered that 37 per cent of 16 to 24-year-olds want to live under sharia law compared to 17 per cent of those over 55.

Roughly a quarter of European Muslims attend religious services on a weekly basis, five times the rate of west European Protestants. There is little evidence that time modifies this pattern. In Britain, home office surveys in 2001 and 2003 reveal that the second generation of south Asian Muslims has about the same proportion of weekly attenders—nearly 40 per cent—as the immigrant generation. This retention rate is thrown into relief by the pace of decline among West Indian Christians: 50 per cent of the first generation attend weekly but only 30 per cent of those British-born. No wonder more Britons attend mosque each week than Church of England services. Findings for Turkish and Moroccan communities in Holland show a slight dip in attendance for the second generation, but no slackening in religious belief or identification.

The net result of a young Muslim population with high fertility, continuing immigration, strong religious retention and low secularisation is a potential for high growth. But before we jump to conclusions, let`s recognise some important counter-trends. The most notable is the rapid decline in the Muslim birth rate. This is partly due to plummeting fertility rates in immigrant source countries and partly because of assimilation to host society norms. In England and Wales, Pakistani and Bangladeshi immigrant total fertility rates (TFRs) dropped from 9.3 to 4.9 between 1971 and 1996. Both groups now have TFRs of less than three. So there are grounds to think European Muslim fertility will come to resemble that of the majority. Our projections assume convergence by 2030.

So, what does the future hold? Our projections for many west European countries find that Muslims will make up between 4 and 14 per cent of the population by 2030, a large increase from the 2-6 per cent range today, but a far cry from Eurabia. Sweden will be the most Islamic country in Europe. Britain`s Muslim population will be close to 7 per cent, compared to 2.8 per cent in 2001 (and a 2009 estimate of 4 per cent). Some might be tempted to glide from careful projection to a prophecy of a doubling of the Muslim share every 20 years. This would produce a Muslim majority in a few generations and vindicate the predictions of extreme Eurabianists.

However, this is misguided for two reasons. First, Muslim fertility is falling. Second, non-Muslim immigrant groups are also growing fast, making Europe more plural and less Islamic. Though our report does not venture beyond 2030, further projections for Switzerland are revealing. If Muslim fertility converges to host levels by 2030, the Muslim proportion only reaches 8.5 per cent in Switzerland and 14 per cent in Austria by 2050. Looking ahead still further, Austria`s Muslim population only rises to 21.5 per cent by 2100 while in Switzerland it tops out at a mere 10.5 per cent. Those of “other” religions like Hindus or Buddhists comprise around 15 per cent in both countries by 2100, creating a “Pluropa” of Christians, seculars, Muslims and others.

These are much larger Muslim numbers than exist today, and will create majorities in some places. Yet they fall well shy of a Eurabian reconquest. That said, Youssef Courbage`s work shows that in recent years, the fertility decline of several European Muslim groups, notably Turks and north Africans, has slowed, partly because of Islamist pressure. David Coleman in Britain, and the Swedish and Norwegian statistical agencies, assume that the lower socioeconomic status and religious and ethnic particularities of Muslim groups will maintain fertility above average for the foreseeable future. Higher immigration from the Muslim world is also a possibility. If this is true, Muslim growth may continue beyond 2100.

But should the decline in Muslim fertility stop, we will be on course to meet the predictions of the cautious Eurabianists. Switzerland`s Muslim total would reach 23 per cent by 2100, and 40 per cent of its under-14s would be Muslim. Austria`s Muslim share would be 17 per cent in 2050 and 36 per cent in 2100, with 54 per cent of under-14s being Muslim.

Even if higher Muslim fertility rates do not persist, Islam will make a significant imprint on European life—so saner Eurabian ideas should be publicly discussed. Nonetheless, the overwhelming weight of demographic evidence points towards a decline in Muslim fertility and a more plural Europe. It seems to me that the bigger worry by the second half of the 21st century will be an emerging “culture war” between fundamentalists of all faiths and those who back the secular status quo. Muslim-origin seculars will make common cause with white seculars against Islamists and other fundamentalists. Sadly, this is a clash that fundamentalists are poised to win because fertility differences based on theology do not fade like those based on ethnicity. This phenomenon, which political science professor James Guth dubs “religious restructuring,” is well in train in the US. Once upon a time, Catholics had larger families than Protestants. Catholic fertility converged to Protestant levels by 1980, but the fertility gap between mainly secular pro-choice and pro-life (read: fundamentalist) women across all religions widened: from 22 to 38 per cent between 1972 and 2006.

Thus theological differences within faiths came to matter more than the ethnic differences between them. This is most apparent among American and British Jews, where the ultra-Orthodox have a threefold fertility advantage over their liberal counterparts and better retain their members. Academics Yaakov Wise and Joshua Comenetz predict an ultra-Orthodox majority in British and American Jewry by 2050. In Israel, a third of Jewish six year olds come from ultra-Orthodox families, which are on track to form the majority by 2100. Europe`s Christians are much less fecund, but European women who attend church regularly are more fertile than non-attenders at all levels of income or education. Among French women born in 1960, practising Catholics bear a half child more than those who don`t practise. Urk, an orthodox Calvinist village in southern Holland, has the youngest population in the country. Across all creeds, theological conservatives are expanding at the expense of seculars and liberals.

Europe`s Muslims reflect this polarisation. Part of this is ethnic. French Muslims of Algerian descent, many of whom, like footballer Zinedine Zidane, are Berber and not Arab, are far more secular and likely to marry out than other Muslim groups. Over half of Franco-Algerian men marry non-Muslims and 60 per cent of French people with at least one Algerian parent say they have no religion. In Germany, Iranian Muslims, many of whom come from anti-Islamist families, tend to be less religious than other groups. A third claim to be completely secular and almost three-quarters never attend religious events. Balkan and central Asian Muslims in Germany also tend to be less religious. But even within Muslim ethnic groups, the study finds an important polarisation between the devout who pray daily and the equally large number who never pray. This divide maps on to fertility: the most devout Muslim women in Europe are 40 per cent more likely than the least pious to bear three or more children. In the large cities of the Muslim world, women most in favour of sharia bear twice as many children as those most opposed.

And fundamentalists are reaching out across faith lines to combat secularism. Once again, the US has set the tone: 86 per cent of practising Catholics under 40 backed the Catholic John F Kennedy in 1960. By 2004, 74 per cent of young conservative Catholics opted for evangelical George W Bush over their co-religionist John Kerry. So, incidentally, did two-thirds of Orthodox Jews, despite the overall Jewish record of voting Democratic. Today, religious intensity is more important than denomination in predicting how people vote. Conservative Protestants, Catholics, Mormons and Jews tend to vote Republican while their more liberal co-religionists and seculars back the Democrats. Prior to 9/11, Muslims participated in this alignment. At a large conference of American Muslims in 2000, Republican presidential hopeful Pat Buchanan said to resounding applause: “American Muslims are sometimes described as patriarchal-authoritarian, believers in large families… It sounds to me very much like my own father.”

The new interfaith fundamentalism can be found in both domestic and international politics. California`s 2008 anti-gay marriage initiative, proposition eight, passed on the strength of Latino, Catholic and black Protestant votes, with white evangelicals, Catholics and Mormons providing much of the grassroots organisation. Overseas, as journalist Michelle Goldberg has described, the Family First Foundation (FFF) welds Catholic, Mormon and evangelical activists with a smattering of conservative Jews and Muslims to lobby against family planning and women`s equality at the UN. The FFF`s Allan Carlson also spearheaded the World Congress of Families (WCF), a regular gathering at which dignitaries from the Vatican, Saudi and Iranian Islamists and evangelicals break bread and plan their attacks on UN policies. WCF co-founder Richard Wilkins, for instance, has links with al-Jazeera`s radical talkshow host Yusuf al-Qaradawi. He also joined hands with Wahhabi fundamentalists to build the Doha International Institute for Family Studies and Development in Qatar.

So it seems likely that Europe`s conservative Muslims will one day join forces with conservative Christians to advance a American-style values agenda. It is a far safer strategy for conservatives in liberal democracies than the ethnic nationalist card, which political correctness makes hard to play. Robert Putnam and others contend that growing diversity erodes social solidarity and support for the welfare state. If the American example is anything to go by, growing conflict over values accompanies this loss of solidarity. Protestant Americans long worried about a Catholic takeover through immigration but now find themselves joining hands with Catholic allies on both sides of the culture war. In the Pluropa of the next century, fears of Islamic conquest may also fade as seculars and fundamentalists of all kinds struggle for the soul of Europe.